Brachytherapy is a form of cancer treatment in which radiation sources are placed inside a patient's body, e.g., to irradiate a tumor. In brachytherapy, a physician typically implants several radioactive seeds in or around a tumor, thereby providing a higher radiation dose to the tumor than would be possible with external beam radiation therapy. Careful placement of the radioactive seeds is critical to allow for localized and precise irradiation of the tumor.
Cervix applicators using radiation in the treatment of cervical cancer have been in existence since the discovery of Radium in the early 19th century. Historically, Radium sources (sealed sources) were placed in ovoids attached to tubes and thereafter inserted “manually” into vaginal or intrauterine cavities for the treatment of cancer. The insertion of the applicator was associated with significant radiation exposure to the physicians handling the apparatus.
Henschke et al. at Memorial Hospital in New York is believed to have introduced the “Afterloading Technique” in 1960, in which applicators are inserted first and the radioactive materials thereafter. Other isotopes, such as cesium-137 and iridium-192 sources have slowly replaced Radium. Cervix applicators have been developed in many different versions, and one widely accepted today is the Fletcher-Suit-Delclos (FSD) applicator. This applicator consists of two lateral ovoids and one central tandem. The ovoids can be spread laterally and fixed in place. The tandem is floating, and packing is required. Applicators in use today are considered “manual afterloading applicators”.
In the early 1980s, High-Dose-Rate (HDR) Remote Afterloading is believed to have been introduced in the United States. These units provided greater protection from radiation exposure to staff and personnel. Applicators were inserted “cold” in specially shielded rooms, and the radioactive sources were inserted “remotely” from control consoles located outside the treatment room. The HDR break-through featured sealed sources much smaller in size than radium or cesium sources and opened new treatment possibilities and with it new opportunities in applicator designs.